1. Field of the Invention
The present invention generally relates to photodetector mountings for special telescopic gun sights, and more specifically, to sights mounted in high vibration environments, such as in helicopters.
2. Description of Prior Art
The Army's helicopter gunships include camera systems boresighted with one or more of their guns to determine their overall effectiveness and provide a permanent record of damage to specific targets. To provide special optical sights for these guns, the film carrier in the camera system can be temporarily replaced by a gimbal mounted detector. The camera optics, which remain firmly mounted to the helicopter, are used by the special sight to focus a target image on the detector. This arrangement is described in U.S. Pat. No. 5,138,156 entitled "Vibration Tolerant Boresight Mechanism" by John E. Lee, et al., to issue on Aug. 11, 1992.
The detector is mounted on the axis of a circularly cylindric housing and this housing axis is aligned with the optical axis of the camera optics by means of the gimbal mounting. A coaxial cable is connected to the detector to supply dc power to the detector, if needed, and to transmit detector signals to an external amplifier. The housing has circular end walls with center apertures to admit the cable at one end and the radiation from the camera optics at the opposite end. The detector and its cable are moved axially within the housing to place the light sensitive surface of the detector at the focal plane of the camera optics.
While this arrangement solved some of the mechanical problems of shock and vibration, the external amplifier proved to be electrically noisy and, since it had no mounting was poorly protected. Since the amplifier was designed specifically for use with this particular detector and aircraft, no off-the-shelf solution is available.
What is needed in this instance is a simpler detector and amplifier combination to eliminate the source of noise between the detector and amplifier and to provide better protection for the amplifier.